Critically Endangered

What "Critically Endangered" means

Critically Endangered is the highest-risk category for species still living in the wild on the IUCN Red List, the global inventory of extinction risk run by the International Union for Conservation of Nature.

A species is Critically Endangered when the evidence shows it faces an extremely high risk of extinction in the wild. It's the most severe of the three "threatened" categories:

1. Vulnerable: high risk
2. Endangered: very high risk
3. Critically Endangered: extremely high risk

The next step up is Extinct in the Wild. The official abbreviation is CR. As of 2026, more than 10,000 species on the Red List are Critically Endangered.

How a species qualifies

A species qualifies as Critically Endangered if it meets any one of five criteria. In simplified form:

• A: Rapid decline. The population has fallen, or is expected to fall, by 80% to 90% or more over 10 years or three generations, whichever is longer.
• B: Tiny, shrinking range. An extent of occurrence under 100 km², or an area of occupancy under 10 km², that is fragmented or declining.
• C: Small, declining population. Fewer than 250 mature individuals, and still declining.
• D: Extremely small population. Fewer than 50 mature individuals.
• E: Modeling. At least a 50% chance of extinction in the wild within 10 years or three generations.

A species doesn't have to be tiny in number to qualify. The African penguin still had roughly 19,800 mature birds in 2024 when it was listed as Critically Endangered, because its population is falling so fast.

"Possibly extinct"

IUCN won't declare a species extinct until thorough, targeted surveys have failed to find it. Until then, a species that may already be gone stays Critically Endangered with a "Possibly Extinct" or "Possibly Extinct in the Wild" tag. These tags are not separate categories.

Critically Endangered vs. the Endangered Species Act

The U.S. Endangered Species Act has no "critically endangered" listing. It uses only "endangered" and "threatened," decided by U.S. agencies. The two systems are separate, so the IUCN and ESA status of the same animal can differ.

Critically Endangered animals at the zoo

Accredited U.S. zoos care for many Critically Endangered species, including the western gorilla, orangutan, black rhinoceros, California condor and red wolf. For species this rare, zoo populations managed through Species Survival Plans can be a lifeline. The California condor is the classic example: every remaining wild bird was brought into human care in 1987, and captive-bred condors have been released back into the wild since the early 1990s through reintroduction.